call from "computer service department", vaguely official-sounding, pretending to "fix" a problem I don't have.

it sounds like they're just dialing numbers from the phone book and trying to scam people.  this isn't the first call of this type.

very annoying and dishonest.  (just try asking them exactly what type of computer they THINK you're having the problem with - and tell them you've been looking for help with your C<64 system for years.)